JP6993285B2 - Internal combustion engine control device - Google Patents

Description

The present invention relates to a control device for an internal combustion engine.

Patent Document 1 discloses a technique for executing or stopping oil injection from an oil jet to a piston in order to suppress deposit accumulation in the piston, depending on the temperature of the piston and the fuel injection amount.

Japanese Unexamined Patent Publication No. 2017-145757

It has been found that such a deposit grows and the amount of deposit increases as a predetermined running state is repeatedly performed. In the above-mentioned Patent Document 1, since such a viewpoint is not taken into consideration, there is a possibility that the deposit accumulation cannot be effectively suppressed.

Therefore, an object of the present invention is to provide a control device for an internal combustion engine capable of effectively suppressing the accumulation of deposits in a piston.

The above object is in a control device for an internal combustion engine that stops oil injection when the rotation speed and load factor of the internal combustion engine mounted on the vehicle belong to a stop region for stopping oil injection from the oil jet to the piston. The maximum value of the altitude difference in the traveling route with high traveling frequency is equal to or more than the threshold value, the vehicle speed of the vehicle belongs to a predetermined range, and the operating state of the internal combustion engine belongs to a predetermined high rotation speed low load region. When there are more than a predetermined number of times within a predetermined period, it can be achieved by the control device of the internal combustion engine that expands the stop region to the side where the rotation speed of the internal combustion engine is high.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a control device for an internal combustion engine capable of effectively suppressing deposit accumulation in a piston.

FIG. 1 is a diagram showing an engine to which the control device of this embodiment is applied. FIG. 2 is an example of a map showing an oil injection stop region in which oil injection is stopped and an oil injection execution region in which oil injection is executed. FIG. 3 is a flowchart showing an example of the control executed by the ECU.

FIG. 1 is a diagram showing an engine 20 to which the control device of this embodiment is applied. The engine 20 is an example of an internal combustion engine, in which the air-fuel mixture is burned in the combustion chamber 23 in the cylinder head 22 installed on the cylinder block 21 in which the piston 24 is housed, and the piston 24 is reciprocated. The reciprocating motion of the piston 24 is converted into the rotational motion of the crankshaft 26. An oil pan 21a for storing lubricating oil is provided in the lower part of the cylinder block 21. Although not shown, the engine 20 is an in-line 4-cylinder engine having four cylinders, but the engine 20 is not limited thereto. The engine 20 is mounted on the vehicle as a traveling source.

The cylinder head 22 of the engine 20 is provided with an intake valve 42 for opening and closing the intake port 10i and an exhaust valve 44 for opening and closing the exhaust port 30e for each cylinder. Further, a spark plug 27 for igniting the air-fuel mixture in the combustion chamber 23 is attached to the top of the cylinder head 22 for each cylinder.

The intake port 10i of each cylinder is connected to the surge tank 18 via a branch pipe of each cylinder. An intake pipe 10 is connected to the upstream side of the surge tank 18, and an air cleaner 19 is provided at the upstream end of the intake pipe 10. The intake pipe 10 is provided with an air flow meter 15 for detecting the intake air amount and an electronically controlled throttle valve 13 in order from the upstream side.

Further, a port injection valve 12 for injecting fuel into the intake port 10i is installed in the intake port 10i of each cylinder. The fuel injected from the port injection valve 12 is mixed with the intake air to form an air-fuel mixture, and this air-fuel mixture is sucked into the combustion chamber 23 when the intake valve 42 is opened, compressed by the piston 24, and ignited by the spark plug 27. Be burned.

The exhaust port 30e of each cylinder is connected to the exhaust pipe 30 via a branch pipe for each cylinder. The exhaust pipe 30 is provided with a three-way catalyst 31. An air-fuel ratio sensor 33 for detecting the air-fuel ratio of the exhaust gas is installed on the upstream side of the three-way catalyst 31.

An oil jet 53 for injecting oil in the oil pan 21a onto the back surface side of the piston 24 is provided. The oil sucked by the oil pump 50 is injected from the oil jet 53 via the oil strainer 51. A control valve 52 is provided between the oil pump 50 and the oil jet 53, and the amount of oil injected from the oil jet 53 is adjusted according to the opening degree of the control valve 52. The temperature of the piston 24 is lowered by injecting oil from the oil jet 53 to the piston 24. Further, as will be described in detail later, when the operating state of the engine 20 belongs to a predetermined region, the oil injection is stopped by fully closing the control valve 52.

The ECU (Electronic Control Unit) 60 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory). The ECU 60 controls the engine 20 by executing a program stored in RAM or ROM. The ECU 60 is a control device for the engine 20.

The above-mentioned spark plug 27, throttle valve 13, and port injection valve 12 are electrically connected to the ECU 60. Further, the ECU 60 includes an accelerator opening sensor 11 for detecting the accelerator opening, a throttle opening sensor 14 for detecting the throttle opening of the throttle valve 13, an air flow meter 15 for detecting the intake air amount, an air fuel ratio sensor 33, and a crank shaft. The crank angle sensor 25 that detects the crank angle of 26, the water temperature sensor 29 that detects the temperature of the cooling water of the engine 20, the control valve 52 described above, and various other sensors are electrically connected. The ECU 60 controls the spark plug 27, the throttle valve 13, the port injection valve 12, etc. so that a desired output can be obtained based on the detection values of various sensors, and the ignition timing, fuel injection amount, fuel injection timing, etc. Control the throttle opening, etc.

The storage device of the navigation device 90 is mounted on the vehicle on which the engine 20 is mounted, and stores map data, past travel history of the vehicle 1, and the like. Further, the navigation device 90 has a built-in GPS (Global Positioning System) receiver that acquires the position information of the vehicle 1. The ECU 60 is electrically connected to the navigation device 90.

Here, a deposit may be accumulated on the top surface of the piston 24 due to the oil injection from the oil jet 53 to the piston 24. For example, when the operating state of the engine 20 is low rotation and low load, the pressure in the combustion chamber 23 is lower than the pressure in the oil pan 21a due to the relatively small throttle opening, and the oil is discharged to the combustion chamber 23. It is easy to be drawn in, and the temperature of the piston 24 tends to be low. Therefore, when the operating state of the engine 20 is a low rotation speed and a low load, a deposit is likely to occur. When the operating state of the engine 20 is low rotation and low load, the ECU 60 stops oil injection from the oil jet 53.

FIG. 2 is an example of a map showing an oil injection stop region in which oil injection is stopped and an oil injection execution region in which oil injection is executed. In FIG. 2, the horizontal axis shows the rotation speed [rpm] of the engine 20, and the vertical axis shows the load factor [%] of the engine 20. The oil injection stop region is set to an operating region where the piston 24 is not hot enough to require cooling with oil. For example, the upper limit of the rotation speed in the oil injection stop region is set to 3000 rpm. By stopping the oil injection in the operating region where deposits are likely to occur in this way, the generation of deposits is suppressed.

However, even if the oil injection stop region is set as described above, the deposit is on the piston 24 because the running state in which the operating state of the engine 20 becomes high rotation and low load is repeated frequently within a predetermined period. It was found that the deposits were increased by occurring and growing in the area. Therefore, the ECU 60 of the present embodiment suppresses the accumulation of deposits by expanding the oil injection stop region so as to include high rotation and low load when such a predetermined running state is repeated. The control for changing the oil injection stop region will be described below.

FIG. 3 is a flowchart showing an example of the control executed by the ECU 60. First, based on the information stored in the navigation device 90, it is determined whether or not the maximum altitude difference, which is the maximum value of the altitude difference on the traveling route where the vehicle travels frequently, is equal to or greater than the threshold value H. (Step S1). The navigation device 90 stores home registration position information, information on travel routes with high travel frequency, and map data including altitude. Based on this information, the ECU 60 calculates the altitude difference on the traveling route with high traveling frequency and acquires the maximum altitude difference.

When traveling on a route with a large difference in altitude, the acceleration and deceleration of the vehicle tend to be slow, and when going down a slope, for example, the vehicle speed tends to increase even if the accelerator opening is small. That is, when traveling on a route having a large difference in altitude, it can be considered that the operating state of the engine 20 tends to be high rotation and low load. If a negative determination is made in step S1, this control ends.

In the case of an affirmative determination in step S1, it is determined whether or not the traveling time of the vehicle is included between 10:00 PM and 7:00 AM (step S3). The traveling time of the vehicle is stored in the navigation device 90, and the ECU 60 acquires and determines the information stored in the navigation device 90. When the traveling time of the vehicle is included between 10:00 PM and 7:00 AM, it can be considered that the vehicle has traveled in an environment where the outside air temperature is relatively low. The above time zone is just an example and is not limited to this.

When the vehicle travels in an environment where the outside air temperature is relatively low, the temperature of the intake air introduced into the combustion chamber 23 is also relatively low, so that the temperature inside the combustion chamber 23 tends to decrease and deposits tend to accumulate. If a negative determination is made in step S3, this control ends. If the affirmative determination is made in step S3, the first flag is turned ON (step S5).

Next, it is determined whether or not the state in which the vehicle speed is equal to or higher than the threshold value V, the rotation speed of the engine 20 is equal to or higher than the threshold value R, and the load factor of the engine 20 is lower than the threshold value K continues for 15 seconds or longer. (Step S7). The vehicle speed is acquired based on the vehicle speed sensor mounted on the vehicle, the rotational speed of the engine 20 is acquired based on the crank angle sensor 25, and the load factor of the engine 20 is acquired based on the air flow meter 15. For example, the threshold value V is 70 Km / h, the threshold value R is 3000 rpm, and the threshold value K is 15%. The process of step S7 is executed for each trip. The above threshold values and the period of 15 seconds are merely examples and are not limited to these.

When the vehicle speed is equal to or higher than the threshold value V, it can be considered that the vehicle is not in an idle state but in a running state. In this running state, when the rotation speed of the engine 20 is equal to or higher than the threshold value R and the load factor is less than the threshold value K, it is considered that the running state of the engine 20 is high rotation and low load, and the deposit can grow in the running state. It can be regarded as something. When this running state is continued for 15 seconds or more, it can be regarded as a running state in which the deposit can grow and the deposit amount can increase.

If a negative determination is made in step S7, step S11, which will be described later, is executed. If the affirmative determination is made in step S7, the second flag is turned ON (step S9).

After the execution of step S9 or the negative determination in step S7, it is determined whether or not two weeks or more have passed since the previous determination of whether or not the oil injection stop region has been changed (step S11). Note that 2 weeks is just an example and is not limited to this. Step S11 will be described later.

If a negative determination is made in step S11, this control ends. In the case of an affirmative determination in step S11, the number of times A in which the first flag is turned on and the number of times B in which the second flag is turned on in the most recent past month are counted (step S13). Next, it is determined whether or not the number of times A is equal to or greater than the threshold value α and the number of times B is equal to or greater than the threshold value β (step S15). The threshold values α and β are not limited to, for example, 90 times, and the threshold values α and β may be different values. In addition, one month is just an example and is not limited to this.

If a positive determination is made in step S15, the oil injection stop region is expanded (step S17). Specifically, the upper limit of the rotation speed in the oil injection stop region is changed from the initial value of 3000 rpm to the higher side of 4000 rpm as shown in FIG. As a result, the high rotation and low load are included in the oil injection stop region, and the oil injection is stopped when the operating state of the engine 20 belongs to the high rotation and low load region, so that the accumulation of deposit can be effectively suppressed. The above-mentioned initial value of the upper limit value of the rotation speed in the oil injection stop region and the upper limit value after expansion are merely examples and are not limited to this.

In the case of a negative determination in step S15, it is determined whether or not the oil injection stop region has been expanded (step S19). If the affirmative determination is made in step S19, the oil injection stop region is reduced (step S21). When the affirmative judgment is made in step S19, the oil injection stop area was expanded last time, but this time it is considered that the frequency of the running state where the operating state of the engine 20 is high rotation and low load is low, and the oil injection stop is performed. There is no need to keep the area expanded. For example, the upper limit of the oil injection stop region is changed from 4000 rpm to the initial value of 3000 rpm.

If a negative determination is made in step S19, this control ends. In this case, although the altitude difference in the traveling path of the vehicle is large, it is considered that the frequency of the traveling state in which the operating state of the engine 20 is high rotation and low load is low, and there is no need to expand the oil injection stop region. Is.

As described above, when it is determined that the running state in which the deposit grows and the deposit amount tends to increase is frequently repeated, the oil injection stop region is expanded and the deposit deposit is suppressed. Further, in step S11 described above, the presence or absence of the change of the oil injection stop region is performed after two weeks have passed, and the frequent change of the oil injection stop region is suppressed.

Although the examples of the present invention have been described in detail above, the present invention is not limited to such specific examples, and various modifications and variations are made within the scope of the gist of the present invention described in the claims. It can be changed.

In the above embodiment, the route for the ECU 60 to acquire the altitude difference on the traveling route with high traveling frequency is not limited to the information from the navigation device 90. For example, information indicating the current position of the vehicle is constantly transmitted to a server installed outside the vehicle, and this server uses the frequently traveled travel route of the vehicle, the altitude difference within the travel route, and the altitude difference. Any one of the maximum elevation difference, which is the maximum value of, may be transmitted to the ECU 60, and the ECU 60 may acquire the maximum elevation difference based on this information.

The time zone of step S3 may be different depending on the region and the season. Further, instead of step S3, the first flag may be turned ON when the deposit is likely to be accumulated in a predetermined season or in a predetermined area. Instead of step S3, the temperature information in the traveling time around the traveling route may be acquired, and the first flag may be turned ON when the average temperature in the traveling time is within a predetermined range. The temperature information may be, for example, the outside air temperature acquired from a temperature sensor mounted on the vehicle, or the temperature information acquired from weather information or the like. Note that step S3 is not always necessary. This is because, depending on the type of engine, the outside air temperature at the running time may not easily affect the deposit accumulation.

The degree to which the oil injection stop region is expanded may be set according to the above-mentioned number of times A and B. For example, when the number of times A and B are 50 or more and less than 90 times, the upper limit of the rotation speed in the oil injection stop region is expanded from the initial value of 3000 rpm to 3500 rpm, and the times A and B are 90 times or more, respectively. In some cases, the upper limit may be expanded from the initial value of 3000 rpm to 4000 rpm. The same applies when the oil injection stop area is reduced.

Further, the expansion of the oil injection stop region may be carried out step by step. For example, the upper limit is expanded from the initial value of 3000 rpm to 3500 rpm at the first time when the oil injection stop area is expanded, and then the upper limit is expanded from 3500 rpm to 4000 rpm when the oil injection stop area is expanded again. You may. The same applies when the oil injection stop area is reduced.

20 engine (internal combustion engine)
23 Combustion chamber 24 Piston 60 ECU (control device for internal combustion engine)
90 Navigation device

Claims (1)

In the control device of the internal combustion engine that stops the oil injection when the rotation speed and the load factor of the internal combustion engine mounted on the vehicle belong to the stop region where the oil injection from the oil jet to the piston is stopped.
The maximum value of the altitude difference in the traveling path where the vehicle travels frequently is equal to or higher than the threshold value, the vehicle speed of the vehicle belongs to a predetermined range, and the operating state of the internal combustion engine belongs to a predetermined high rotation / low load region. A control device for an internal combustion engine that expands the stop region to the side where the rotation speed of the internal combustion engine is high when the number of times is greater than or equal to a predetermined number of times within a predetermined period.

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